[AAS08-14] The response of extreme variability in the Arctic stratosphere to 4xCO2 concentrations in CMIP6 models
Keywords:sudden stratospheric warmings, climate change
In this work, we use this new model output to investigate the response, if any, of extreme variability in the Arctic stratosphere to 4xCO2 forcing. The results of many models predict that the SSW frequency is sensitive to increase in CO2 loading, but there is a large disagreement across models on the sign of this change. Regarding the SSW impact on the troposphere, the response over the North Atlantic remain unchanged, but the signal over the Pacific is more uncertain, with some indications that there might be a larger mean response under 4xCO2 scenario. Finally, the models show robust changes to the seasonal cycle in the stratosphere. Specifically, we find an earlier formation of the vortex in Autumn and a delay in the date of SFWs, resulting in a longer duration of the polar vortex and so, of the season of stratosphere-troposphere coupling.